Division 5 Reagents and materials

Unless otherwise stated, use only reagents of a purity greater than 97 %, purchased from an ISO-accredited supplier with a certificate of purity, free from other congeners at test dilution (this may be confirmed by injection of individual congener standards at the test dilution using GC conditions as in 6.4) and only water of at least grade 3 as defined in ISO 3696. Acetal and acetaldehyde must be stored in the dark at < 5 °C, all other reagents may be stored at room temperature.

1. 5.1.

   Ethanol absolute (CAS 64-17-5).

2. 5.2.

   Methanol (CAS 67-56-1).

3. 5.3.

   Propan-1-ol (CAS 71-23-8).

4. 5.4.

   2-methylpropan-1-ol (CAS 78-33-1).

5. 5.5.

   Acceptable internal standards: pentan-3-ol (CAS 584-02-1), pentan-1-ol (CAS 71-41-0), 4-methylpentan-1-ol (CAS 626-89-1) or methyl nonanoate (CAS 1731-84-6).

6. 5.6.

   2-methylbutan-1-ol (CAS 137-32-6).

7. 5.7.

   3-methylbutan-1-ol (CAS 123-51-3).

8. 5.8.

   Ethyl acetate (CAS 141-78-6).

9. 5.9.

   Butan-1-ol (CAS 71-36-3).

10. 5.10.

    Butan-2-ol (CAS 78-92-2).

11. 5.11.

    Acetaldehyde (CAS 75-07-0).

12. 5.12.

    Acetal (CAS 105-57-7).

13. 5.13.

    40 % v/v ethanol solution

    To prepare 400 ml/l ethanol solution pour 400 ml ethanol (5.1) into a 1-litre volumetric flask, make up to volume with distilled water and mix.

14. 5.14.

    Preparation and storage of standard solutions (procedure used for the validated method).

    All standard solutions must be stored at < 5 °C and be prepared freshly on a monthly basis. Masses of components and solutions should be recorded to the nearest 0,1 mg.

    1. 5.14.1.

       Standard solution — A

       Pipette the following reagents into a 100-ml volumetric flask, containing approximately 60-ml ethanol solution (5.13) to minimise component evaporation, make up to volume with ethanol solution (5.13) and mix thoroughly. Record the weight of the flask, each component added and the total final weight of contents.

       Component	Volume (ml)
       Methanol (5.2)	3,0
       Propan-1-ol (5.3)	3,0
       2-methylpropan-1-ol (5.4)	3,0
       2-methylbutan-1-ol (5.6)	3,0
       3-methylbutan-1-ol (5.7)	3,0
       Ethyl acetate (5.8)	3,0
       Butan-1-ol (5.9)	3,0
       Butan-2-ol (5.10)	3,0
       Acetaldehyde (5.11)	3,0
       Acetal (5.12)	3,0

       Note 1:

       It is preferable to add acetal and acetaldehyde last in order to minimise losses through evaporation.

    2. 5.14.2.

       Standard solution — B

       Pipette 3 ml of pentan-3-ol, or other suitable internal standard, (5.5) into a 100-ml volumetric flask, containing approximately 80 ml ethanol solution (5.13), make up to volume with ethanol solution (5.13) and mix thoroughly.

       Record the weight of the flask, the weight of pentan-3-ol or other internal standard added and the total final weight of contents.

    3. 5.14.3.

       Standard solution — C

       Pipette 1 ml solution A (5.14.1) and 1 ml solution B (5.14.2) into a 100-ml volumetric flask containing approximately 80 ml ethanol solution (5.13), make up to volume with ethanol solution (5.13) and mix thoroughly.

       Record the weight of the flask, each component added and the total final weight of contents.

    4. 5.14.4.

       Standard solution — D

       In order to maintain analytical continuity, prepare a quality control standard using the previously prepared standard A (5.14.1). Pipette 1 ml solution A (5.14.1) into a 100-ml volumetric flask containing approximately 80 ml ethanol solution (5.13), make up to volume with ethanol solution (5.13) and mix thoroughly.

       Record the weight of the flask, each component added and the total final weight of contents.

    5. 5.14.5.

       Standard solution — E

       Pipette 10 ml solution B (5.14.2) into a 100-ml volumetric flask containing approximately 80 ml ethanol solution (5.13), make up to volume with ethanol solution (5.13) and mix thoroughly.

       Record the weight of the flask, each component added and the total final weight of contents.

    6. 5.14.6.

       Standard solutions used to check the linearity of response of FID

       Into separate 100-ml volumetric flasks, containing approximately 80 ml ethanol (5.13), pipette 0, 0,1, 0,5, 1,0, 2,0 ml solution A (5.14.1) and 1 ml solution B (5.14.2), make up to volume with ethanol solution (5.13) and mix thoroughly.

       Record the weight of the flask, each component added and the total final weight of contents.

    7. 5.14.7.

       QC standard solution

       Pipette 9 ml standard solution D (5.14.4) and 1 ml of standard solution E (5.14.5) into a weighing vessel and mix thoroughly.

       Record the weight of the flask, each component added and the total final weight of contents.